The invention is directed to a gold containing preparation for coating metallic particles, particularly for coating fired on alloys in the dental art before the facing with ceramic compositions, consisting of gold powder, an adhesive and a binder of one or more organic solvents and one or more resin components, which binder is liquid at room temperature and volatilized or burned at firing temperature.
For many years in the dental art there has been known the facing of crowns and bridges made of fired on alloys with ceramic compositions. Thereby chiefly for aesthetic reasons the metallic crown or bridge framework is entirely or partially coated with one or more tooth colored ceramic layers. Likewise primarily for aesthetic reasons gold-rich intermediate layers are used which bestow a warmer colored background to the slightly transparent dental porcelain as is possible by the generally metallic white customary fired on alloys.
The previously known gold containing intermediate layer preparations lead to very smooth surfaces and cannot be effectively influenced by the dental technician.
The formation of the frequently desired grooves or relief type differences in height on the surfaces of the crowns and bridges thus is not possible. The previously known gold preparations were either melted or sintered and contain gold powder or ball-shaped gold particles (German AS 2851429) which leads to a uniform layer thickness and a very smooth surface.
On the other hand there has also long been known the significance of a sufficient dovetailing between the metallic fired on alloys and the dental ceramic for a good union. The preparation of the so-called physical union depends directly very strongly on the size, the shape and the roughness of the surface to be joined with the ceramic.
Besides all previously known preparations for intermediate layers have the disadvantage that they have a relatively high gold requirement of the great difficult in influencing the coating thickness.
Therefore it was the problem of the present invention to develop gold containing preparations for the coating of metallic portions, particularly for the coatings of fired on alloys in the dental art before the facing with ceramic compositions consisting of gold powder, an adhesive agent and a binder which is liquid at room temperature and is volatilized or burned at firing temperature, which after the firing guarantees the strongest possible dovetailing with the dental ceramic, has an aesthetic appearance and makes possible a saving in the use of gold.